Introduction: Developing Intelligence Theory

As this special issue of Intelligence and National Security on 'Developing Intelligence Theory' is published, it is a decade since its three editors decided to put together an initial volume presenting the current state of conceptual thinking about intelligence. Stephen Marrin provides an evaluative review of the theoretical literature on intelligence that has been published since the Intelligence Theory volume. Comparative analysis should not be just spatial but also temporal: intelligence has been a presence in almost all societies, ancient and modern. From early democratic orders to the contemporary liberal–democratic state; one question that prompted early contributors to the academic literature on intelligence was that of the impact of intelligence practice on liberal–democratic politics. Brantly notes: '… intelligence analysis is at the dawning of a new era, a digital era in which information collected from everything from toasters and coffeemakers can now be incorporated with human sources'.